1/*
2 * Copyright (C) 2001-2004 Aurelien Jarno <aurelien@aurel32.net>
3 * Ported to Linux 2.6 by Aurelien Jarno <aurelien@aurel32.net> with
4 * the help of Jean Delvare <jdelvare@suse.de>
5 *
6 * This program is free software; you can redistribute it and/or modify
7 * it under the terms of the GNU General Public License as published by
8 * the Free Software Foundation; either version 2 of the License, or
9 * (at your option) any later version.
10 *
11 * This program is distributed in the hope that it will be useful,
12 * but WITHOUT ANY WARRANTY; without even the implied warranty of
13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
14 * GNU General Public License for more details.
15 *
16 * You should have received a copy of the GNU General Public License
17 * along with this program; if not, write to the Free Software
18 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
19 */
20
21#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
22
23#include <linux/module.h>
24#include <linux/init.h>
25#include <linux/slab.h>
26#include <linux/i2c.h>
27#include <linux/mutex.h>
28#include <linux/err.h>
29#include <linux/hwmon.h>
30
31/* Insmod parameters */
32
33static int input_mode;
34module_param(input_mode, int, 0);
35MODULE_PARM_DESC(input_mode,
36 "Analog input mode:\n"
37 " 0 = four single ended inputs\n"
38 " 1 = three differential inputs\n"
39 " 2 = single ended and differential mixed\n"
40 " 3 = two differential inputs\n");
41
42/*
43 * The PCF8591 control byte
44 * 7 6 5 4 3 2 1 0
45 * | 0 |AOEF| AIP | 0 |AINC| AICH |
46 */
47
48/* Analog Output Enable Flag (analog output active if 1) */
49#define PCF8591_CONTROL_AOEF 0x40
50
51/*
52 * Analog Input Programming
53 * 0x00 = four single ended inputs
54 * 0x10 = three differential inputs
55 * 0x20 = single ended and differential mixed
56 * 0x30 = two differential inputs
57 */
58#define PCF8591_CONTROL_AIP_MASK 0x30
59
60/* Autoincrement Flag (switch on if 1) */
61#define PCF8591_CONTROL_AINC 0x04
62
63/*
64 * Channel selection
65 * 0x00 = channel 0
66 * 0x01 = channel 1
67 * 0x02 = channel 2
68 * 0x03 = channel 3
69 */
70#define PCF8591_CONTROL_AICH_MASK 0x03
71
72/* Initial values */
73#define PCF8591_INIT_CONTROL ((input_mode << 4) | PCF8591_CONTROL_AOEF)
74#define PCF8591_INIT_AOUT 0 /* DAC out = 0 */
75
76/* Conversions */
77#define REG_TO_SIGNED(reg) (((reg) & 0x80) ? ((reg) - 256) : (reg))
78
79struct pcf8591_data {
80 struct device *hwmon_dev;
81 struct mutex update_lock;
82
83 u8 control;
84 u8 aout;
85};
86
87static void pcf8591_init_client(struct i2c_client *client);
88static int pcf8591_read_channel(struct device *dev, int channel);
89
90/* following are the sysfs callback functions */
91#define show_in_channel(channel) \
92static ssize_t show_in##channel##_input(struct device *dev, \
93 struct device_attribute *attr, \
94 char *buf) \
95{ \
96 return sprintf(buf, "%d\n", pcf8591_read_channel(dev, channel));\
97} \
98static DEVICE_ATTR(in##channel##_input, S_IRUGO, \
99 show_in##channel##_input, NULL);
100
101show_in_channel(0);
102show_in_channel(1);
103show_in_channel(2);
104show_in_channel(3);
105
106static ssize_t out0_output_show(struct device *dev,
107 struct device_attribute *attr, char *buf)
108{
109 struct pcf8591_data *data = i2c_get_clientdata(to_i2c_client(dev));
110 return sprintf(buf, "%d\n", data->aout * 10);
111}
112
113static ssize_t out0_output_store(struct device *dev,
114 struct device_attribute *attr,
115 const char *buf, size_t count)
116{
117 unsigned long val;
118 struct i2c_client *client = to_i2c_client(dev);
119 struct pcf8591_data *data = i2c_get_clientdata(client);
120 int err;
121
122 err = kstrtoul(buf, 10, &val);
123 if (err)
124 return err;
125
126 val /= 10;
127 if (val > 255)
128 return -EINVAL;
129
130 data->aout = val;
131 i2c_smbus_write_byte_data(client, data->control, data->aout);
132 return count;
133}
134
135static DEVICE_ATTR_RW(out0_output);
136
137static ssize_t out0_enable_show(struct device *dev,
138 struct device_attribute *attr, char *buf)
139{
140 struct pcf8591_data *data = i2c_get_clientdata(to_i2c_client(dev));
141 return sprintf(buf, "%u\n", !(!(data->control & PCF8591_CONTROL_AOEF)));
142}
143
144static ssize_t out0_enable_store(struct device *dev,
145 struct device_attribute *attr,
146 const char *buf, size_t count)
147{
148 struct i2c_client *client = to_i2c_client(dev);
149 struct pcf8591_data *data = i2c_get_clientdata(client);
150 unsigned long val;
151 int err;
152
153 err = kstrtoul(buf, 10, &val);
154 if (err)
155 return err;
156
157 mutex_lock(&data->update_lock);
158 if (val)
159 data->control |= PCF8591_CONTROL_AOEF;
160 else
161 data->control &= ~PCF8591_CONTROL_AOEF;
162 i2c_smbus_write_byte(client, data->control);
163 mutex_unlock(&data->update_lock);
164 return count;
165}
166
167static DEVICE_ATTR_RW(out0_enable);
168
169static struct attribute *pcf8591_attributes[] = {
170 &dev_attr_out0_enable.attr,
171 &dev_attr_out0_output.attr,
172 &dev_attr_in0_input.attr,
173 &dev_attr_in1_input.attr,
174 NULL
175};
176
177static const struct attribute_group pcf8591_attr_group = {
178 .attrs = pcf8591_attributes,
179};
180
181static struct attribute *pcf8591_attributes_opt[] = {
182 &dev_attr_in2_input.attr,
183 &dev_attr_in3_input.attr,
184 NULL
185};
186
187static const struct attribute_group pcf8591_attr_group_opt = {
188 .attrs = pcf8591_attributes_opt,
189};
190
191/*
192 * Real code
193 */
194
195static int pcf8591_probe(struct i2c_client *client,
196 const struct i2c_device_id *id)
197{
198 struct pcf8591_data *data;
199 int err;
200
201 data = devm_kzalloc(&client->dev, sizeof(struct pcf8591_data),
202 GFP_KERNEL);
203 if (!data)
204 return -ENOMEM;
205
206 i2c_set_clientdata(client, data);
207 mutex_init(&data->update_lock);
208
209 /* Initialize the PCF8591 chip */
210 pcf8591_init_client(client);
211
212 /* Register sysfs hooks */
213 err = sysfs_create_group(&client->dev.kobj, &pcf8591_attr_group);
214 if (err)
215 return err;
216
217 /* Register input2 if not in "two differential inputs" mode */
218 if (input_mode != 3) {
219 err = device_create_file(&client->dev, &dev_attr_in2_input);
220 if (err)
221 goto exit_sysfs_remove;
222 }
223
224 /* Register input3 only in "four single ended inputs" mode */
225 if (input_mode == 0) {
226 err = device_create_file(&client->dev, &dev_attr_in3_input);
227 if (err)
228 goto exit_sysfs_remove;
229 }
230
231 data->hwmon_dev = hwmon_device_register(&client->dev);
232 if (IS_ERR(data->hwmon_dev)) {
233 err = PTR_ERR(data->hwmon_dev);
234 goto exit_sysfs_remove;
235 }
236
237 return 0;
238
239exit_sysfs_remove:
240 sysfs_remove_group(&client->dev.kobj, &pcf8591_attr_group_opt);
241 sysfs_remove_group(&client->dev.kobj, &pcf8591_attr_group);
242 return err;
243}
244
245static int pcf8591_remove(struct i2c_client *client)
246{
247 struct pcf8591_data *data = i2c_get_clientdata(client);
248
249 hwmon_device_unregister(data->hwmon_dev);
250 sysfs_remove_group(&client->dev.kobj, &pcf8591_attr_group_opt);
251 sysfs_remove_group(&client->dev.kobj, &pcf8591_attr_group);
252 return 0;
253}
254
255/* Called when we have found a new PCF8591. */
256static void pcf8591_init_client(struct i2c_client *client)
257{
258 struct pcf8591_data *data = i2c_get_clientdata(client);
259 data->control = PCF8591_INIT_CONTROL;
260 data->aout = PCF8591_INIT_AOUT;
261
262 i2c_smbus_write_byte_data(client, data->control, data->aout);
263
264 /*
265 * The first byte transmitted contains the conversion code of the
266 * previous read cycle. FLUSH IT!
267 */
268 i2c_smbus_read_byte(client);
269}
270
271static int pcf8591_read_channel(struct device *dev, int channel)
272{
273 u8 value;
274 struct i2c_client *client = to_i2c_client(dev);
275 struct pcf8591_data *data = i2c_get_clientdata(client);
276
277 mutex_lock(&data->update_lock);
278
279 if ((data->control & PCF8591_CONTROL_AICH_MASK) != channel) {
280 data->control = (data->control & ~PCF8591_CONTROL_AICH_MASK)
281 | channel;
282 i2c_smbus_write_byte(client, data->control);
283
284 /*
285 * The first byte transmitted contains the conversion code of
286 * the previous read cycle. FLUSH IT!
287 */
288 i2c_smbus_read_byte(client);
289 }
290 value = i2c_smbus_read_byte(client);
291
292 mutex_unlock(&data->update_lock);
293
294 if ((channel == 2 && input_mode == 2) ||
295 (channel != 3 && (input_mode == 1 || input_mode == 3)))
296 return 10 * REG_TO_SIGNED(value);
297 else
298 return 10 * value;
299}
300
301static const struct i2c_device_id pcf8591_id[] = {
302 { "pcf8591", 0 },
303 { }
304};
305MODULE_DEVICE_TABLE(i2c, pcf8591_id);
306
307static struct i2c_driver pcf8591_driver = {
308 .driver = {
309 .name = "pcf8591",
310 },
311 .probe = pcf8591_probe,
312 .remove = pcf8591_remove,
313 .id_table = pcf8591_id,
314};
315
316static int __init pcf8591_init(void)
317{
318 if (input_mode < 0 || input_mode > 3) {
319 pr_warn("invalid input_mode (%d)\n", input_mode);
320 input_mode = 0;
321 }
322 return i2c_add_driver(&pcf8591_driver);
323}
324
325static void __exit pcf8591_exit(void)
326{
327 i2c_del_driver(&pcf8591_driver);
328}
329
330MODULE_AUTHOR("Aurelien Jarno <aurelien@aurel32.net>");
331MODULE_DESCRIPTION("PCF8591 driver");
332MODULE_LICENSE("GPL");
333
334module_init(pcf8591_init);
335module_exit(pcf8591_exit);
336